Thanks so much for all of the comments and suggestions. This is extremely helpful for my project at this stage.

I admit I'm not too educated about the whole subject, so let me know if any of my answers below need further research in your opinion.

Regarding adding GUI elements (David's suggestion) - I can see how important that would be, but I'd like to focus on basic game graphics for now. Also, there's another GSoC project by Sam Bull that approaches a GUI framework for Pygame.

As for collision detection (Nicholas' and DR0ID's emails): I agree with DR0ID's concerns about maintaining a clear scope for the project, and I can understand that collisions are more the engine's job than the sprite classes. However, as the current Sprite module includes many of the functions related to that, I thought I could get into that as part of my work.

I'm guessing that implementing a basic and naive code wouldn't be too hard, but the question remains would doing that be an elegant design.

I want to research how this kind of features is done on similar libraries. I would also love to get your thoughts on that. So this is still an open question for now.

Aggregated sprites: I think the use case DR0ID has mentioned is good enough for implementing that. I'm thinking about writing the aliens.py game so that the aliens are a group of sprites moving together, while each one could have a different behavior when needed.

Dirty rendering: Again, this doesn't seem to me as something that's too difficult to implement, and would definitely help any non-scrolling game, which I think is a pretty solid use case.

I gather that the most requested features are probably:

1. Better positioning, particularly using float values.

2. Anchor points.

3. Visual attributes.

4. A smarter layers system.

5. Sprite picking.

I will research each of these during the week.

If you have any more comments or additions please do reply to this thread.

I'll also be idling in #pygame most of the time and would love to chat.

DR0ID - I'll be happy to set a time to chat and learn more about all of your suggestions.

2. the sprites anchor point should be just an offset, not limited to 'topleft', 'midtop', 'topright',... and the other rect attributes

I want to be able to specify "center" or "midbottom" for the sprite anchor without knowing the image's dimensions. And I want that anchor point to remain in the appropriate place even if the image is rotated, scaled, or flipped. I'm not sure that an offset would accomplish this, but if so, then that's okay.